Bismuth-213 for Targeted Radionuclide Therapy: From Atom to Bedside

In contrast to external high energy photon or proton therapy, targeted radionuclide therapy (TRNT) is a systemic cancer treatment allowing targeted irradiation of a primary tumor and all its metastases, resulting in less collateral damage to normal tissues. The α-emitting radionuclide bismuth-213 (²¹³Bi) has interesting properties and can be considered as a magic bullet for TRNT. The benefits and drawbacks of targeted alpha therapy with ²¹³Bi are discussed in this review, covering the entire chain from radionuclide production to bedside. First, the radionuclide properties and production of ²²⁵Ac and its daughter ²¹³Bi are discussed, followed by the fundamental chemical properties of bismuth. Next, an overview of available acyclic and macrocyclic bifunctional chelators for bismuth and general considerations for designing a ²¹³Bi-radiopharmaceutical are provided. Finally, we provide an overview of preclinical and clinical studies involving ²¹³Bi-radiopharmaceuticals, as well as the future perspectives of this promising cancer treatment option.